The 950 different species of sea urchins live in water of all temperatures, warm or cold. Some species prefer to live in the shallows, on coral reefs or among kelp forests, while others find their home in deep, rocky seabeds. The Sea urchin population has grown by 10,000% in the last five years, which saw purple sea urchins ravage the coasts of California and Oregon in 2019. Scientists believe it could take 15-20 years to remove almost 100 million pounds of sea urchin from one large Oregon reef alone!